Exhaust gas muffler



' July 14, 1931. F. F. HAMILTON ET AL EXHAUST GAS MUFFLER Filed Dec. 5, 1928 3 Sheets-Sheet l [N V Talrfi. Franc/'6 Hamilton, '4 Harold E, Van year/tee y Wa m,

A Hon-149 July 14, 1931. F. F. HAMILTON ET AL EXHAUST GAS MUFFLER 5, 1928 3 Sheets-Sheet 2 Filed Dec,

by W *MLZTL I July 14, 1931. F. F. HAMILTON ET AL 1,815,005

EXHAUS T GAS MUFFLER Filed Dec. 5, 1928 5 Sheets-Sheet 3 A tiornejm Patented July 14, 1931 UNITED STATES PATEN SFFICE FRANCIS F. HAMILTON AND HAROLD E. VAN VOORHEES, OF INDIANAPOLIS,

. INDIANA EXHAUST GAS MUFFLER Application. filed December 5, 1928.

This. invention relates to mufliers for exhaust gases and has for its primary objects a simple inexpensive construction of a muffier, the peculiar formation of which will 6 eliminate the back pressure of the gases heretofore encountered in mufiling gases and at the same time eliminate all sound.

Other objects will become apparent in the following description of the invention made 10 in reference to the accompanying drawings,

in which,-

Fig. 1 is a fragmentary side elevation of a muflier embodying the invention;

Fig. 2, a horizontal, longitudinal section 15 through the mufiler on the line 22 in Fig. 3, a vertical transverse section on the line 3-3 in Fig. 1;

Fig. 4, a vertical transverse section on the 2 line 1-4 in Fig. 1;

Fig. 5, a fragmentary elevation of a muffler-modified from the form shown in Fig. 1; Fig. 6, a vertical transverse section on the line 6-6 in Fig.

,5 Fig. 7, a further modified form of the invention in fragmentary side elevation;

Fig. 8, a vertical transverse section on the line 8-8 in Fig. 7;

Fig. 9, a still further modified form of the 80 invention in fragmentary side elevation; and

Fig. 10, a rear elevation of the mufiier shown in Fig. 9.

Like characters of reference indicate like parts throughout the several views in the 3. drawings.

Referring first to Figs. 1-4, we form a housing closed at both ends and substantially ellipsoidal in transverse cross-section by pressing out the two similar halves and 16, the two halves being welded toether therearound on a median plane to form the gas tight joint 17 therebetween.

A pipe 18 is entered through the forward end of the housing at the median plane but toward one side of the housing on the horizontal center line, and is joined to the.

halves l5 and 16 in a gas tight joint. The pipe 18 extends substantially to the rear of the housing where it fits over a boss 19 eX- tending into the pipe 18 from the plate 20.

Serial No. 323,831.

The plate Q0 encloses the rear end of the pipe 18 by the concave cap 21, the balance of the plate 20 being extended eccentrically therearound and having an annular flange 22 over which the tube 28 fits snugly. 5

The tube 23 extends forwardly about the pipe 18, and has a visor 2d attached therearound at its forward open end to project toward the opposite side of the housing, Figs. 1, 2, and 3, the opening between or clearance around the visor and the housing, being approximately uniform in width therearound. The tube 23 is preferably supported by a bracket 50 at the front and welded between the tube and pipe.

The pipe 18 is provided with a plurality of holes 25 along its side which lies nearest the tube :23, an increasingly larger number of holes 25 being provided from the forward end to the rear end. The pipe 18, by its outer forward end, is intended to receive the exhaust gases. Such gases entering the pipe 18 may escape laterally therefrom through the holes 25, some of the gas escaping through the holes 25 nearest the forward end, while other parts of the gas travel along in the pipe to escape from holes 25 further removed from the forward end, the difference in number of holes 25 near the forward and back ends being such as to induce a discharge of gas all along the pipe 18 from the holes 25, rather than permitting all the gas to discharge through the first encountered holes 25.

The gases coming through the holes 25 5 enter the tube 28, which, being entirely open at its forward end, permits the rapid flow of them therefrom forwardly over and around the visor 2st and back into the housing. The eccentric mounting of the tube 23 in respect to the pipe 18 aids in stretching out the gas. By means of this structure as above described, the gases are in fact broken up or stretched out into various streams of unequal length, the stream passing out the first encountered hole 25 from the forward end being very short as compared to the length of the stream of gases from the last hole in the pipe 18 and then back to the first hole 25 again. Much of the noise of the gases is eliminated by this stretching structure.

In the rear of the housing, an exhaust or tail pipe 26 passes therethrough at the side of the housing removed from that toward which the pipe 18 is placed. On the forward end of the pipe 26 within the housing is mounted a sound trap generally designated by the numeral 27, and described in detail as follows.

On the forward end of the pipe 26 is fitted a hollow frustum of a cone 28 flaring outwardly and forwardly from the pipe 26. This frustum 28 has a plurality of slots 29 therethrough and spaced equally therearound on elemental lines of the frustum, the ends of the slots 29 toward the pipe 26 being in a vertical plane somewhat removed from the pipe 26. A. hollow cone having a completely enclosed wall but open base is extended into the frustum 28 by its apex and secured at its base line around the base line of the frustum.

The altitude of the cone 30 is much less than is that of the cone from which the frustum 28 is taken so that the wall of the cone 30 drops sharply away from the interior wall of the frustum 28 to form a passageway therearound discharging into the pipe 26. An outer hollow frustum 81 surrounds the frustum 28 having its base line in the same plane as the base lines of the cone 30, and the frustum 28, but flaring outwardly from the frustum 28 and rearwardly toward the pipe 26,

Gases in the housing may escape into the frustrum 31 out through the slots 29 over the cone 30 and into the pipe 26 and thence outwardly therefrom. A second hollow cone 32 is secured around its base line by a flange therefrom wrapping around and back of an out-turned lip 33 from the frustum 31 gripping the finge s 84 from the frustum 28 therebetween, so that gases may escape through the annular passage between the bases of the frustum 28 and the cone 82, Fig. 4, into the space between and within the two cones 30 and 32. In some instances it may be desirable to close this passage entirely (not shown) so that the outer sides only of the cones 30 and 32 are contacted by the gases. This sound trap operates to reflect sound waves away from passages communicating to the exterior of the housing by the angular change in flow of the gas streams and angular disposition of the reflecting Walls.

As a further aid in breaking up the flow of sound, we put a deflector around the pipe 26 within the housing, Figs. 1 and 2 flaring outwardly from the pipe and to ward the rear wall of the housing, but terminating at a distance therefrom.

The tube 28 is wrapped with a heat and sound insulating material 86, preferably a directly sheet of asbestos and this material is sur rounded by the retaining cover 37.

The entire structure as above described gives excellent results in eliminating sound and by reducing the pressure of gases coming into the pipe 18 to substantially atmospheric pressure. It is to be noted, that at no place, is the gas forced through an opening or series of openings having a combined area less than that of. the crosssectional area of the pipe 18.

Referring now to Figs. to 10 inclusive, the form shown in Figs. 5 and 6 is employed where there is not sufiicient room for the wide ellipsoidal housing, it being noted that the trap 27 is carried back of .the tube 23 and not up alongside of it as in Fig.1. The form shown in Figs. 7 and 8 show the pipe 18 and tube mounted concentrically with a housing 88 and no sound trap is provided. While such a form will meet the requirement for a cheaper structure than either that shown in Fig. 1 or Fig. 5 it will be somewhat noisier.

The form shown. in Figs. 9 and 10 still embodies the same gas stretching principle as utilized in all of the other forms, but it eliminates the housing around the tube and allows the gases to flow directly out of the forward end of the tube 23 into a collecting head 40 which is in reality a short housing, and out the discharge pipe ell. It is also to be noted that the pipe 18 in both forms shown in Figs. 7, 8, and 9, 1O mounted concentrically within the tube 23 and not eccentrically as in the heretofore described forms, the results not being quite so good as in the first two described forms, but yet much better than in the conventional type of muffler heretofore employed.

The housing in the form shown in Figs. 1, 2, and 3 is preferably stiflened by annular corrugations 12, 13, -14, and internal corrugations 415, 16, and 4-? along the sides and end to eliminate vibration of the walls and to create eddy currents in the gas flow.

Ta e claim 1. 111 a gas mutller, means for obtaining flows of gas of varying lengths comprising a tube open at one end and closed at the other, and a pipe inserted longitudinally within the tube having a plurality of openings spaced apart along the length within the tube, said pipe being much smaller in diameter than the tube and being located eccentrically therein. 2

2. In a gas muflier, a housing, a pipe having perforations along one side, and a tube surrounding said pipe and opening into said housing around its forward end, and a visor turned back from around the forward edge of the tube within the housing, a tail pipe extending from the housing, a sound trap in the housing on the tail pipe, and a deflector on the tail pipe in the housing between the sound trap and the housing wall through which the tail pipe passes.

3. In a gas mufiler, a housing, a pipe having perforations along one side, and a tube surrounding said pipe and opening into said housing around its forward end, a tail pipe extending from the housing, and a sound trap on the pipe comprising a series of nested cones of different altitudes around which the discharge circulates.

4. In a gas mufl'ler, means for obtaining flows of gas of varying lengths comprising a tube open at one end and closed at the other, and a pipe inserted longitudinally within the tube having a plurality of openings spaced apart along the length within the tube, and a housing into which said tube discharges having an exhaust discharge therefrom the walls of said housing having one or more annular inturned corrugations.

5. In a gas muffler, means for obtaining flows of gas of varying lengths comprising a tube open at one end and closed at the other, and a pipe inserted longitudinally and eccentrically within the tube having a plurality of openings spaced apart along the length within the tube on the side closest to the tube, and a housing ellipsoidal in cross section in a focal axis of which the tube is located, and into which said tube discharges having an exhaust discharge therefrom, and means between said tube and said exhaust discharge to intercept and refleet sound waves from the gas flowing to ward said discharge.

6. In a gas inuifler, a housing ellipsoidal in cross section, an intake pipe entering the housing at its forward end and extending to a substantial distance within the housing toward one side, in the median plane of the housing, a cover plate fitted on the end of the pipe and extending transversely therefrom, a tube eccentrically surrounding the pipe within the housing and carried by its rear end by said plate extension whereby said tube is closed across its rear end and held in spaced relation from the pipe, said tube terminating at its forward open end at a distance from the forward end of the housing, and said pipe having holes spaced apart along its length within the tube.

7. In a gas muffler, a housing, an intake pipe entering the housing at its forward end and extending to a substantial distance within the housing, a cover plate fitted on the end of the pipe and extending transversely therefrom, a tube surrounding the pipe within the housing and carried by its rear end by said plate extension whereby said tube is closed across its rear end and held in spaced relation from the pipe, said tube terminating at its forward 0 en end at a distance from the forward end of the housing, said pipe being eccentric to the tube, and said pipe having holes spaced apart along its length within the tube, and a visor turned outwardly and rearwardly from around the forward edge of said tube to define by its periphery a narrow opening therearound between it and the housing.

8. In a gas muffler, a housing, an intake pipe entering the housing at its forward end and extending to a substantial distance within the housing at its forward end, a cover plate fitted on the end of the pipe and extending transversely therefrom, a tube surrounding the pipe within the housing and carried by its rear end by said plate extension whereby said tube is closed across its rear end and held in spaced relation from the pipe, said tube terminating at its forward open end at a distance from the forward end of the housing, and said pipe having holes spaced apart along its length within the tube, and a visor turned outwardly and rearwardly from around the forward edge of said tube to define by its periphery a narrow opening therearound between it and the housing, an exhaust pipe extending to within the housing, a deflector around said exhaust pipe within the housing flaring outwardly and rearwardly toward but not contacting the rear end of said housing, and a plurality of members on the inner end of said exhaust pipe arranged to reflect sound waves from entering said end but permitting the flow of gas thereto.

In testimony whereof we affix our signatures.

FRANCIS F. HAMILTON. HAROLD E. VAN VOORHEES. 

